


Step on a Crack

by Night-Mare (Aoife)



Series: Cracks 'verse - All [6]
Category: Katekyou Hitman Reborn!
Genre: Adorable Murder Babies, Alternate Universe, Dark fic, Estraneo being Estraneo, Flame Active Character(s), Gen, Implied/Referenced Human Experimentation, POV Gokudera Hayato
Language: English
Status: In-Progress
Published: 2017-05-20
Updated: 2018-03-02
Packaged: 2018-11-02 23:43:14
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,541
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10955190
Author URL: https://archiveofourown.org/users/Aoife/pseuds/Night-Mare
Summary: The fifth side story toBetween the Cracks. Part of theCracks 'verse.  Hayato and Mukuro take advantage of the generators' failure to get to their Sky.





	1. Chapter 1

**Author's Note:**

  * For [Saj_te_Gyuhyall](https://archiveofourown.org/users/Saj_te_Gyuhyall/gifts).
  * Inspired by [Between the Cracks](https://archiveofourown.org/works/10896882) by [Night-Mare (Aoife)](https://archiveofourown.org/users/Aoife/pseuds/Night-Mare). 



"Kufufufufufu, looks like our lords and masters fucked up, Hayato-kun." The heterochromatic-eyed Mist murmured into his ear. "The generators haven't come online ... care to get us out of here?"

He grinned, wolfish, and then raised his hands, one the blood red of an enraged Storm, the other the purple of an angry Cloud, and shoved both against the wall. "Do remember to cover our backs, Mukuro." They were speaking in Japanese, a language he had learned from his mother, and the Mist had ripped from the mind of one of the scientists he'd killed. It had the advantage of not being spoken by any of the scientists that were still in the faculty, though neither of them ever spoke particularly loudly. The wall burst outwards in a spray of rubble that took out the guard in the corridor outside, and he threw up a Lightning shield to stop either of them being hit. "Plan A, or Plan B?"

"A. That's _our_ Sky that just went Active." The words are louder, more definite than either of them have been since they saw the last of their original group killed for their insolence. He nodded, also able to feel the immature bond, weaker sibling to the one they shared. "Kufufufufu ... this is going to be so much fun." The Mist 'dissolved', but Mukuro's voice echoed in his ears. "First to ten gets the next choice of dream."

He laughed and the Flames on his hands shaded into something between the original two colours. "You're on." The laughter echoes through the tunnels as the two of them carve their way through the walls and floors, searching for the newly Active Sky their Flames had latched onto; any scientists that got between them and their goal either ended up as fine carbon dust or stabbing themselves with whatever was to hand. The messiest was the scientist who use a pencil to kill himself.

"Kufufufufu ... we'll have to start over. That's a tie." Mukuro's Mist form swirled around the Storm, hiding him from sight while they talked. "And there's another Mist somewhere around here. She'll need some help to get out." Mukuro rematerialised, and floated across to one of the locked doors. "This one."

He smiled, and shifted one hand's Flames back to the red of Storm, and pressed it to the lock of the door, allowing into melt beneath his hand. "Tada!" The door swung open, revealing the unconscious form of a Mist that could have been Mukuro's twin.

"Kufufufufu ... she's me?" The Mist stared at the girl on the medical bed, and stumbled, feet not quite working properly in the transition to actually standing rather than floating, and poked her with one finger. "You can see through their illusions. Are they messing with me?" He watched Mukuro's face, amused, and then brushed Sun Flame covered hands across the pinned lower legs, healing them to the best of his abilities.

"Not an illusion - she really does look like you; but definitely needs a stronger Sun than I am," he tilted his head. "Our Sky has two actual Suns; can you ...?" he left the question unvoiced and open ended, and the two Mists dissolved into something like vapour. It was a shame that Mukuro had never left the compound, or they could have escaped a long time ago.

"She's taking most of my concentration to keep phased, kufufufufu. Watch your own back, for a bit Hayato-kun." He snorted. The Sky at least was close by; and he turned, blasting through another wall. And another, taking out two more scientists as vapour swirled around him. The presence of the vapour kept him from loosing his thread of thought, his desire to find their Sky rather than just kill and kill and kill, and Mukuro kept nudging him towards their destination.

The Sky Flames that rolled over the three of them, as another bond settled into place between their Sky and one of the group with him made Hayato shiver, and slow, melting a hole through the final wall separating them from the Sky purely with Storm Flames rather than blasting through - the group on the other side were about the same age as he and Mukuro, and at the centre, with a Sun working on one prone boy and two sitting ones beside him, was a Sky, with fluffy brown hair and brilliant orange eyes.

He's tiny, their Sky. But impossibly strong. Stronger than he and Mukuro were - the same strength that condemned them to be 'kept' by the scientists who wanted to see if he could be transformed into a Sky, and if the Mist could be 'tamed' and turned to their own desires. And strong enough that it had taken all of the precautions the Estraneo could contrive - for which they had needed their precious generators - to contain them.

And still all encompassing; he'd reached out to them without knowing them, and offered them a home, and now he was standing in front of him. "I'm Hayato." The two Clouds stared at him from where they flanked the little Sky, and he had to fight the urge to flare his own Cloud Flames at them.

"Kaasan calls Tsu-kun, Tsu-kun. They had Hayato-kun, too?" The boy had to be even younger than he thought, to still be talking in the third person. And Japanese; he'd never been so glad he'd learnt Japanese.

"And Mukuro-kun." Mukuro rematerialised next to him, the girl-copy of him unconscious in his arms. "How long have you been here, Tsu-kun?" Their Sky scrunched his nose up like Hayato remembers seeing bunnies do, and it was just as cute.

"Tsu-kun's not sure. Kyoya-san said the bad adults had been messing with the light and the food." The Sky looked at the male Cloud. "Tsu-kun remembered right?"

The older boy, with his dark hair and very Japanese features nodded sharply. "You remembered right, Tsunayoshi." He reached out and ruffled the Sky's hair. "We should move soon. Irie-kun is hurting less, and Yamamoto-kun and Tetsuya-kun will manage." The Cloud was obviously trained, which was at least a little bit of a relief, even if he didn't want to follow someone else - but if they pooled their knowledge and Flames? Maybe they could _succeed_ at getting out.


	2. Chapter 2

It's not much harder to move through the facility with twelve than it was with two or three. Whilst it means there are more bodies to think about behind him, there's also another offensive Flame-type beside him - the male Cloud was most definitely trained and from a Flame-using Family - carving a path for the others to follow him. He catches sight of the others darting left or right occasionally; there are quiet sounds and the occasional scream as the others put the weapons Mukuro created for them to good use on the few Estraneo he and Kyoya didn't just disintegrate.

One of the adult Flame Users tries to stop them, tries to use a child as a meat shield, but his fatal mistake was to not account for there being a Sky in the group. Tsuna's Flames surge at the sight of another child being threatened and there's nothing he can do but ride the influx; it's muted and translated for him, into an energy boost, but the adult looks at them all in shock and keels over, blood running from his mouth and nose, the influx of unregulated energy burning him out.

Kyoya turns to deal with their shared Sky and he hauls the wide eyed blond Tsuna just saved to his feet; there's a quiet "Tsu-kun did good?" behind him, and then they're moving again. The blond is another stormy-type and the three of them make short work of the remaining walls between them and the outside.

The sunlight is bright and _warm_ and smells right; that's how he knows it's real. The Estraneo's adult Mist isn't good enough to fool more than two senses at once. But they're not safe yet. Not until they've either destroyed the Estraneo entirely, or got far enough away that they can regroup under the cover of Mukuro's Flames, and figure out what to do _next_.

"Tsu-kun wants the bad adults _gone_." There's a weird pulling sensation on his Flames, like they're being drained away from him and his new baby Sky is glowing, eyes vivid orange. Then the glow winks out, and Tsuna fold, and there's a disconcerting shaking and rumbling that goes on and on, and on, until there's an enormous pit forming in front of them, and they're all on their knees. He fights the lethargy, using the Cloudy portion of his Flames ruthlessly, and sees the other two Clouds doing the same, struggling to their feet, still wary, still needing to guard the others.

Whatever his Sky _did_ is effective, but it basically guarantees that it's going to draw all of the Flame Familigias' attention to where they are now. That means they still need to _move_ but he has no idea how to get the rest back on their feet. Fortunately Kyoya seems to; the older boy is knelt next to their Sky, using his Flames directly on him, and everything is so quiet, he hears the older boy talk their Sky through _sharing_ that extra energy. He has to have succeeded in putting it in terms that Tsuna had understood, because the others start to perk up, and he feels like he's just woken up from a nap - which is just as well because they need to find cover.


	3. Chapter 3

They only make it a kilometre or so from the pit that used to be their prison, but the boost of energy from his Sky - and the _very_ strong Cloud who was now carrying their shared Sky - only went so far, and they needed to rest, and recover a little bit, and it was better they do it now, before anyone came to investigate. They had at least two hours, perhaps a little more (if he was right about where they were, of course) before the Acerbi or the Marchesi could get men to the site. ≪Do you think you can set up something that’ll allow us all a chance to rest, Mukuro?≫ He asks the question in his mind; he has no secrets from the other boy. Hasn’t since the first traumas that the Estraneo had inflicted on him; it was Mukuro’s Mist they’d tried to force into him, to try and make him a Sky, and it had left them linked.

Prodding their link to communicate gives him an odd feeling, like a third in their mind, and it was uncomfortably like something one of the scientists had tried to use to control them (he’d killed the Adult Mist they’d used, burnt his mind out while Mukuro distracted both him and the scientist, but it had hurt for _days_ ). It wasn’t their Sky; that wasn’t as invasive, and felt, distinctly, of Tsunayoshi’s Sky. Mukuro did the mental equivalent of tilting his head in acknowledgement, and there was almost a buzz in his ears before the Mist answers. ≪Kufufufufufu. Nagi and I will be able to if we can get the other two to help.≫

≪Nagi?≫ It felt like he should know the name; perhaps one of the scientists had mentioned it

There was a shy squeak in the back of his head. ≪My female clone. She's _very_ shy, but she's _mine_ now.≫ Mukuro felt fierce, and almost possessively Cloudy about Nagi, and he’s a little bit amused about how sharing their mental landscape has warped them _both_.

≪Ah.≫ He taps Spanner’s shoulder, and tells the Electric Storm that he needs to talk to their Sky, and Kyoya, and leaves the blonde to guard their rear, and bounds forward to where the other male Cloud was still carrying their tiny Sky. "Kyoya-san?"

"Hn. Carnivore." He rolls his eyes, that's the second time the other Cloud has called him that; he wasn't going to ask why, now, but he takes it as a go ahead.

"We need to den up and rest before we're all exhausted. If we stop now, then we can take turns standing guard." The Cloud turns to look at him, and the little Sky lifts his head from where it had been resting against Kyoya's neck. “If we were in the heart of _that_ Family’s territory, then the nearest Families who might have noticed our escape are over two hours away. They’re not _big_ Families, but they’ll covet us and we still might need to fight. And for that we need at least some rest.”

"Hayato-kun's right." There was orange fire in the little Sky's eyes, and he sounded _very_ sure that he was right. "And he has a plan." He tries to remember what he'd been taught about the known Sky gifts within the Flame famiglias. The Estraneo _couldn't_ have snatched a Giglio Nero or a Vongola, surely? But his new Sky was far too confident for it to _just_ be a Sky’s trust in one of his Elements.

There’s a whole unspoken conversation between Kyoya, and the female Cloud before she drifts back closer to her Lightning. Their relationship made him curious, given the way the Cloud didn’t seem to mind her Lightning babbling cheerfully at her (which was completely at odds with the Clouds he’d been introduced to as his father’s heir). "We need a clearing, or something similar. Mukuro _thinks_ that he and Nagi can use their illusions to hide us while we rest, especially if you and Takeshi aid them."

"Hn." Their Sky makes an amused sound, and tucks his head back into the other Cloud's shoulder. The Electric Rain that had hovered near them while he’d been talking to Kyoya went darting ahead at a glance from the other Cloud, and they keep stumbling forward. It's only a few minutes before they're stumbling into an almost purpose-designed space. (A short examination says that it was; there's evidence of deliberate clearing in the past, and he can just follow the trail of the Flames that indicate the Electric Rain had disposed of what had probably been a sentry.)

≪Suitable, Mukuro?≫

≪It'll do.≫ Kyoya puts their shared Sky down, and then almost without warning, there's a surge of Mist Flames - Mukuro drawing even on his _very_ minor ability - and four of their company, including his Misty Demon, drop to their knees. He sighs and drags each one in turn into the centre of the space where they’ll be safest, cursing Mukuro for his dramatic tendencies. He leaves their little Sky to flit between the now unconscious quartet, and then turns to triage the rest of the group; he needed to figure out who had enough energy left to help him keep watch.

(Without Kyoya encouraging Tsunayoshi to moderate his Flame use, their little Sky’s Flames pool and spread within the area Mukuro had defined, and he twitches as he realises he’s witnessing and instinctive claiming of a small bit of territory, something he’d always thought was _hard_ to do.)

He ends up splitting the first watch at least with the female Cloud and her Lightning - who introduces herself as "Kyoko" and her silent protector as "Hana" - and the three of them circle the clearing, with the others, including all three of the other Lightnings, and both Suns napping in the middle. They'd need to figure out someway to get/find food once they’d all napped to recover fully, but in the meantime sleep would help with their Flames at least a little bit.

(Not that either he or the two girls were really in a state to stand guard; they were just a little less exhausted than the others, but there was no way he’d have talked Kyoya and Tsunayoshi into resting, if they didn’t have _someone_ standing watch.)

* * *

He and Tsunayoshi are first to respond to the ‘threat’. He’s still watching over the others, and experimenting with his Cloud Flames; he’d gotten a good introduction to things you could do with Flames (though no-one had explained the actual mechanics to him), and he was trying to use them on the piece of territory his Sky had created earlier.

The territory is shuddering, and he tries to figure out why; it doesn’t take him very long. There’s another Sky trying to influence the territory, and he concentrates, leaving Tsunayoshi to wake the others. He calms down at least a little bit though, because the Flames taste and smell like sweet meadow hay, and he’s fairly sure he remembers meeting the Sky in question _before_. When the illusion falls, his guess is confirmed, and the young Cavallone had two of the Arcobaleno with him, and he was fairly sure that meant they were _safe_.

He's not _quite_ sure what to do with himself now; he’d wound himself up to stand guard, and as a result his Flames prickled beneath his skin, and he paces at the edge of the clearing, wanting to destroy _something_. "Shishishishishi. Destruction is always so tempting, isn't it." He twitches at the words, snapping around to confront whoever had snuck up on him; the speaker is a blonde, a little taller and a little older than him, wearing a crown. He doesn't recognise him, and the blonde smiles toothily at the look of confusion on his face. "The Prince is Xanxus di Vongola's Storm Officer."

He hisses; that was a name he did know, even if he couldn’t have named the youngest Vongola’s Guardians. The only thing he could remember about him was that his father had been grooming his sister to suit the teen Sky; it was why he’d been encouraging her poison cooking. He shoved that train of thought into a small mental box and nailed it shut. His Family hadn't come for him, and they'd murdered his mother, and he had his own Sky now. "Hayato Gokudera."

"Shishishishishi. The Prince renamed himself, too, when he accepted a Sky, but despite that, the birdie should know his sister has missed him sorely, and is currently being trained to control her poison." The grin on the other's face is bloodthirsty. "The Horse humiliated the birdie's former Family for their negligence of the birdie."

"Good."

"Shishishishishi. The Horse and the Shark are being ridiculous again." It’s a non sequitur, but he’s grateful for it as he’d really rather not think about _them_. They’re chatting almost inconsequentially, sparring gently, and the blonde stills, and then has a handful of knives. He feels the use of Cloud Flames, the multiplication of them from a single template. When he eyes them longingly - as much for the Flame trick as for their lethality - the Storm passes him a pair, and demonstrate the trick for him quickly.

"There's a peasant crawling around in the woods. The Prince thinks he needs to die; the Prince was promised blood, and his will suffice." He stiffens, and trails behind the Prince; he’s annoyed with himself that he allowed one of the Estraneo to get so close to the vulnerable members of his ‘set’. They find the ‘peasant’ about a hundred fifty metres from the tiny patch of territory and the two of them cooperate to _eviscerate_ him. It’s _very_ satisfying. "Shishishishishi. The Prince _approves_ of you." He grins back at the Storm Officer, and there's a wave of Storm Flames that clean the blood off his ragged clothes just before they slip back into the clearing. There was a Mist working in the centre, one that had the appearance of a tear in reality, and that explained why Mukuro had been radiating curiosity in the back of his head since not long after he and the Prince had slipped into the woods; the Cavallone Sky had Tsuna in his lap, and their little Sky had melted into him, obviously trusting the older teen, which made him feel better about trusting his vague previous impressions of Dino Cavallone and not attacking. "The little Vongola is adorable; the Prince hopes he's allowed to kill the stupid Lion who lost him."

He blinks. He hadn't thought that Tsuna actually was a Vongola, though that did explain a _lot_. "It looks like you will be accompanying the Prince back to his Sky’s territory; the others we’ve found are already there." Others? Mukuro focuses all his attention on him at the intense spike of hope.

"Who?" His voice is hoarse; several of the children they’d been kept with had survived the experiments and been sold, and they thought they’d never see them again.

"There's a Misty Rain who looks a bit like a blonde version of your new Sky. An Electric Rain who calls himself Chikusa, and a very excitable Electric Sun -" Those aren't tears at the corners of his eyes. They aren't, and he blinks them away ruthlessly and watches to make sure all the others go through the Mist working, which, once he’s through,closes, leaving the Cavallone and the Arcobaleno behind, presumedly to sweep for any remaining Estraneo.

(The Prince catches him as he finally allows himself to collapse in exhaustion. The older boy mutters something he doesn’t catch, and then he’s being tucked into a pile of blankets, and Ken and Chikusa, and even his sister are there. He _has_ to believe they’re safe.)


End file.
